Thanks for your input, appreciated! A bit of custom isn't a problem (I'm used to do everything custom usually!), but it's good to know there are truly useful existing components which can play well together.
Yes indeed. There are so many existing useful components that there's a whole section of the Programmer's Guide to Drupal [0] called "Common Drupal Programming Mistakes: Programming Too Much." Almost all the Drupal code I write is either integration or patches to existing projects.
